Bio-mechanical prosthetic thumb

ABSTRACT

There is disclosed a biomechanically driven prosthetic thumb assembly. Embodiments include an H-shaped rocker and a distal ring configured to receive a user&#39;s residual thumb, the distal ring and the rocker each independently and rotatively coupled between a coupling tip and a proximal anchor plate configured for affixing to a hand strap secured to a user. The coupling tip is articulated in response to a pulling force of the H-shaped rocker. Additional embodiments include a bidirectional thumb assembly including a ring mounted upon an adjustable ring tendon that is rotatively coupled between a coupling tip and a proximal anchor plate, which is rotatively coupled with a hand strap attached to the user. Vertical movement of the residual thumb within the ring actuates the coupling tip within a vertical plane. Lateral movement of the residual thumb within the ring actuates the coupling tip within a lateral plane. Other embodiments are disclosed.

REFERENCE TO PENDING PRIOR PATENT APPLICATION

This application claims the benefit under 35 U.S.C. 119 (e) of U.S.Provisional Patent Application No. 62/209,833, filed Aug. 25, 2015 byRobert Thompson, Jr., Jon Bengtsson, Anthony Charles Peto, Sydney TyeMinnis, Eric Dennis Klumper, and Bradley Arthur Crittenden, for“BIO-MECHANICAL PROSTHETIC THUMB,” which patent application is herebyincorporated herein by reference.

BACKGROUND

If a person loses a thumb, a thumb segment, or a thumb tip, the resultis impaired performance of the hand. Having an amputated or partiallyamputated thumb inhibits the amputee from performing some of the mostbasic tasks. For example, with a lost thumb or thumb tip, the task oftyping on a computer or simply dialing on a phone keypad becomessignificantly difficult. These types of tasks require actions withprecision that only thumbs are able to offer. Not only do thumbs allowpeople to perform precise actions, but the opposing nature of the thumbin relation to the remaining fingers provides the hand with an increasedability to lift and/or handle items. While holding an item in one hand,the weight of the item is dispersed throughout the user's thumb andfingers. By simply varying the force applied by the thumb on each of theholder's hands, the holder is able to manipulate the item(s) in a myriadof ways. However, if the holder is missing a single thumb or a portionof a single thumb, the amount of control available to manipulate theitem(s) is dramatically decreased.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key aspects oressential aspects of the claimed subject matter. Moreover, this Summaryis not intended for use as an aid in determining the scope of theclaimed subject matter.

On embodiment provides a prosthetic thumb assembly. The prosthetic thumbassembly may include (1) a coupling tip, (2) a distal ring configured toconcentrically receive a residual thumb of a user, the distal ringhaving a first operable hinged connection with the coupling tip, (3) aproximal anchor plate having a second operable hinged connection withthe distal ring, and an anchor attachment point configured forrotatively connecting the proximal anchor plate to the user, and (4) arocker formed in an H-shape having a first end and a second end inopposition to one another, the first end forming a first split prong ofthe H-shape, the first end having a third operable hinged connectionwith the coupling tip, the second end forming a second split prong ofthe H-shape, the second end having a fourth operable hinged connectionwith the proximal anchor plate, where (a) the first and second operablehinged connections define a midline relative to a z-axis, (b) the thirdoperable hinged connection is located below the midline, (c) the fourthoperable hinged connection is located above the midline, and (d) thecoupling tip is articulated in response to a pulling force provided bythe rocker.

Another embodiment provides a biomechanically driven prosthetic thumb.The biomechanically driven prosthetic thumb may include (1) a couplingtip, (2) a proximal anchor plate configured for attachment to a handstrap, the hand strap configured for attachment about a hand of a user,(3) a distal ring having a body with an outer surface and an innersurface, the inner surface configured to concentrically receive aresidual thumb of the user, and (4) an H-shaped rocker offset from theouter surface of the body of the distal ring, wherein the distal ringand the H-shaped rocker are independently and pivotally suspendedbetween the coupling tip and the proximal anchor plate via a distalcoordinated pivot point anchored upon the coupling tip and a proximalcoordinated pivot point anchored upon the proximal anchor plate.

Yet another embodiment provides a bidirectional prosthetic thumb device.The bidirectional prosthetic thumb device may include an eccentricarticulation pivot attached to a hand strap and an articulation assemblyrotatively coupled with the eccentric articulation pivot. Thearticulation assembly may include a coupling tip, a proximal anchorplate, and an adjustable ring tendon having a distal end and a proximalend in opposition to one another, the distal end pivotally attached tothe coupling tip and the proximal end pivotally attached to the proximalanchor plate. The articulation assembly may also include a ringconfigured to concentrically receive a residual thumb of a user, thering in operable connection with the adjustable ring tendon, andselectively positionable at a target location between the distal end andthe proximal end of the adjustable ring tendon. The articulation pivotmay be configured to utilize abduction and adduction movements of theresidual thumb within the ring to articulate the coupling tip within aplane parallel to an x-y plane and about an axis parallel to a z-axis,and the articulation assembly may be configured to utilize verticalmovements of the residual thumb within the ring to articulate thecoupling tip within a plane parallel to an x-z plane and about one ormore axes parallel to a y axis.

Additional objects, advantages and novel features of the technology willbe set forth in part in the description which follows, and in part willbecome more apparent to those skilled in the art upon examination of thefollowing, or may be learned from practice of the technology.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive embodiments of the present invention,including the preferred embodiment, are described with reference to thefollowing figures, wherein like reference numerals refer to like partsthroughout the various views unless otherwise specified. Illustrativeembodiments of the invention are illustrated in the drawings, in which:

FIG. 1 illustrates a perspective view of one embodiment of a prostheticthumb assembly;

FIG. 2 illustrates a front view of the prosthetic thumb assembly of FIG.1;

FIG. 3 illustrates a rear view of the prosthetic thumb assembly of FIG.1;

FIGS. 4-5 illustrate respective top and bottom perspective views of theprosthetic thumb assembly of FIG. 1, as attached to a hand of a user viaa hand strap;

FIG. 6 illustrates a top view of the prosthetic thumb assembly of FIG.1;

FIG. 7 illustrates a side view of the prosthetic thumb assembly of FIG.1;

FIG. 8 illustrates a rear view of the prosthetic thumb assembly of FIG.1, with a proximal anchor plate removed;

FIG. 9 illustrates a perspective view of an alternative prosthetic thumbassembly and corresponding hand strap;

FIG. 10 illustrates another perspective view of the prosthetic thumbassembly of FIG. 9; and

FIG. 11 illustrates a bottom perspective view of the prosthetic thumbassembly of FIG. 9.

DETAILED DESCRIPTION

Embodiments are described more fully below in sufficient detail toenable those skilled in the art to practice the system and method.However, embodiments may be implemented in many different forms andshould not be construed as being limited to the embodiments set forthherein. The following detailed description is, therefore, not to betaken in a limiting sense.

Various embodiments disclosed herein relate to a custom-designed,self-contained prosthetic thumb that may be fitted for a user with anamputated thump, thumb tip, or thumb segment. The streamlined,sophisticated, and biomechanically driven design allows for a patientwith any level of residual thumb to utilize a mechanical replacementthat mimics the motions and functionalities of a real thumb. The naturalaction of the prosthetic thumb assembly allows users to regain maximumcontrol of the flexion and extension movements of a full thumb and thumbtip and is designed to bend and curl in a realistic, natural manner inresponse to movement in the user's residual thumb, thumb joint, and/oradjacent fingers.

Embodiments described herein feature specially designed components, suchas an H-shaped tendon or rocker and/or a cupped receiving tip, bothdiscussed in detail below, that allow the prosthetic thumb to anchor toany length of residual thumb while protecting the amputation siteagainst further injury or hypersensitivity and providing the individualuser with maximum fit and use flexibility, dexterity, grip strength, andarticulation.

FIGS. 1-3 illustrate perspective, front, and rear views of oneembodiment of a prosthetic thumb 100. In this embodiment, prostheticthumb 100 may include four major interconnected components that extendfrom a proximal end located at the user's hand to a distal end locatedat a distance from the user's hand. These components include a proximalanchor plate 102, a distal ring 104, a coupling tip 106, and an H-shapedrocker 108. For installation purposes, distal ring 104 may have a body110 that forms a ring shape that is designed to receive and encircle auser's residual thumb. More specifically, body 110 may be configured toanchor about a proximal phalange of a user's residual thumb with a snugfit. Proximal anchor plate 102 may be positioned above and anchoredadjacent to the user's metacarpophalangeal (MCP) joint 130 using a handstrap 132, as shown in FIGS. 4-5. Embodiments of hand strap 132 may haveany appropriate configuration necessary or appropriate to secureproximal anchor plate 102 in a proper position relative to the user'sMCP joint 130, such that manipulation of the joint in relation toproximal anchor plate 102 actuates a number of hinged connections ofprosthetic thumb 100.

In further detail, a series of hinges may be used to secure the fourprimary components discussed above via rotative connections. In oneembodiment, these rotative connections may be particularly positionedwith respect to a pair of axes detailed in FIGS. 6-7. More specifically,FIG. 6 depicts a centerline, C, that bisects prosthetic thumb 100relative to a y-axis, and FIG. 7 shows a midline, M, that intersects afirst hinged connection 112 and a second hinged connection 114, bothdetailed below, relative to a z-axis.

Turning to the various rotative connections detailed in FIGS. 1 and 7,distal ring 104 may rotatively couple with coupling tip 106 via firsthinged connection 112. First hinged connection 112 may include a pair ofparallel pivotal hinges that are symmetric about centerline, C,discussed above in relation to FIG. 6. Each of the pivotal hinges offirst hinged connection 112 may provide a pivot point between distalring 104 and coupling tip 106.

Distal ring 104 may rotatively couple with proximal anchor plate 102 viasecond hinged connection 114. Second hinged connection 114 may alsoinclude a pair of parallel pivotal hinges that are symmetric about thecenterline, C, one located on each side of prosthetic thumb such thateach provides a pivot point between distal ring 104 and coupling tip106. As discussed above in relation to FIG. 7, the midline, M,intersects first and second hinged connections 112, 114, and therefore,both first and second hinged connections 112, 114 are located directlyupon the midline, M, relative to the z-axis.

Rocker 108 may form an H-shape having opposing first and second ends120, 122, respectively, that extend between coupling tip 106 andproximal anchor plate 102. First end 120 may form a first split prong ofthe H-shape, which may rotatively couple with coupling tip 106 via athird hinged connection 116 located below the midline, M, relative tothe z-axis (FIG. 7). Second end 122 of rocker 108 may form a secondsplit prong of the H-shape, which may rotatively couple with proximalanchor plate 102 via a fourth hinged connection 118 located above themidline, M, relative to the z-axis (FIG. 7). Each of third and fourthhinged connections 116, 118 may include a pair of parallel pivotalhinges that are symmetric about the centerline, C, each providing arespective pivot point between rocker 108 and coupling tip 106 at thefirst end 120 and proximal anchor plate 102 at the second end 122.

Any one or more of the first, second, third, and/or fourth hingedconnections 112, 114, 116, 118 may feature a hard-stop to preventhyperextension of prosthetic thumb 100 during operation. For example, ahard-stop 124, shown in FIGS. 1 and 6, may prevent relativeover-rotation of first hinged connection 112, or between coupling tip106 and distal ring 104. Mechanical hard-stops may have any appropriatesize, shape, and/or configuration.

In this embodiment, first and third hinged connections 112, 116 mayalign to form a distal coordinated pivot point 117, which is anchoredupon coupling tip 106. Similarly, second and fourth hinged connections114, 118 may align to form a proximal coordinated pivot point 119, whichis anchored upon proximal anchor plate 102. While distal ring 104 andH-shaped rocker 108 do not directly connect with one another, eachdirectly and pivotally connects with coupling tip 106 and proximalanchor plate 102 via the distal and proximal coordinated pivot points117, 119, respectively. As a result, rocker 108 and distal ring 104 areeach independently, pivotally suspended between coupling tip 106 andproximal anchor plate 102, such that they articulate in coordinated, yetindependent, manners relative to one another and about numerous axesparallel to the y-axis. This association of rocker 108 and distal ring104, without an actual direct link or connection between the twocomponents, allows for complex, realistic vertical articulation motions(e.g., motions within planes parallel to the x-z plane) of coupling tip106 in response to biomechanical input forces exerted by the residualthumb on proximal anchor plate 102 and distal ring 104.

Working together, proximal anchor plate 102, distal ring 104, couplingtip 106, and rocker 108 form a 4-bar linkage system that allows couplingtip 106 to be articulated in response to a pulling force on distal ring104, much like the working framework of tendons within the human hand.In this regard, the linkage created by hinged connections 112, 114, 116,and 118 allow both distal ring 104 and H-shaped rocker 108 to beindependently and rotatively suspended between coupling tip 106 andproximal anchor plate 102. While distal ring 104 is rotatively connectedbetween coupling tip 106 and proximal anchor plate 102 through first andsecond hinged connections 112 and 114, and while rocker 108 isrotatively connected between coupling tip 106 and proximal anchor plate102 through third and fourth hinged connections 116 and 118,respectively, distal ring 104 and rocker 108 are not directly connected.This allows for complimentary, yet independent movement of each ofdistal ring 104 and rocker 108 in relation to one another. Both partsmove in response to movement of the user's residual thumb within distalring 104 and/or movement of the user's MCP joint beneath proximal anchorplate 102, and the nature of the indirect connection between the twocomponents provides for complex, reactive motions to pulling forcesprovided the hand, thereby enabling thumb 100 to emulate naturalmovements.

The pulling force applied either by the residual thumb or by the MCPjoint places the distal ring 104 in tension and reduces the risk ofbuckling. Thus, natural movement of the patient's residual thumb seatedwithin distal ring 104, or in some cases movement of the MCP jointand/or the adjacent fingers, may be used to actuate realistic flexionand extension motions within prosthetic thumb 100. Users may performtheir full range of usual activities, including typing, playing amusical instrument, lifting and manipulating intricate and/or awkwardobjects, and any other activities that require the full dexterity of thehand.

The H-shape of rocker 108 allows third hinged connection 116 betweenrocker 108 and coupling tip 106 to occur outside the assembly of thumb100, or outside the physical boundary defined by distal ring 104 andcoupling tip 106. This configuration allows users with a relativelylonger residual thumb, or a relatively long proximal phalanx, to takeadvantage of additional clearance space within the assembly. Residualthumbs of varying lengths may fit comfortably within the assembly, whilestill being protected against further damage and/or hypersensitivity.That said, while rocker 108 is described herein as having an H-shapedprofile, it should be understood that rocker 108 may take anyappropriate size, shape, type, and/or configuration.

Embodiments of prosthetic thumb 100 are custom designed and individuallyfitted to accommodate a variety of differing user conditions, includingdifferent residual-thumb lengths (e.g., varying amounts of loss to thethumb). In this regard, each thumb 100 may be customized to fit aparticular patient or user, providing both custom functionality as wellas a mechanical match to the anatomical joint articulation of theparticular user, including matching the length of the original,non-amputated thumb. Design considerations include an amount of thumbloss, a number of joints to be replaced, and other characteristicsspecific to the individual end user.

H-shaped rocker 108 is designed to provide a full-coverage “cage” aboveand about a patient's residual thumb, thereby protecting the residualthumb from irritation and/or hypersensitivity, without interfering withthe residual thumb within the prosthetic device 100. Outfitted withH-shaped rocker 108, a user may anchor any length of residual thumbwithin prosthetic thumb 100, even if the residual thumb length extendspast the interphalangeal joint. In cases in which the user has a fullyformed, but poorly or nonfunctioning thumb, coupling tip 106 may beremoved so that prosthetic thumb 100 may function as a joint brace,rather than a digit replacement. Alternatively, coupling tip 106 mayinclude a cup or a recess that is adapted to receive all or a portion ofthe thumb tip in instances in which the patient has experienced littleor no digit loss, but who does not have a fully functioning thumb.

In the embodiment shown in FIGS. 1-8, coupling tip 106 may include a tippad 126. Tip pad 126 may be formed from a soft-textured silicone orother material that mimics the texture of a real thumb tip. This aidswith gripping and provides a softer touch. In one embodiment, atouchscreen mechanism (not shown) may be provided to allow the user touse prosthetic thumb 100 to operate capacitive touchscreens, which reactto the body's natural electrical current. The touchscreen mechanismallows the user to direct his or her own body current through the tip ofthe prosthetic thumb.

One embodiment of coupling tip 106 may also include a thumbnail 128,which mimics a natural edged nail that may provide scratching andpeeling functionalities as well as assist with fine-object manipulation.

To further provide better aesthetics, embodiments of thumb 100 may becoated with films and/or colorings matched to the user's skin tone. Anadditive manufacturing process (i.e., 3D printing) facilitates thisability to customize the intricacies of the prosthetic thumb design inorder to optimize prosthetic thumb 100 for each user.

Embodiments of prosthetic thumb 100 may be formed of any suitablestructural material this is non-irritating to human skin and allows theuser to operate the prosthetic with comfort and confidence. Exemplarymaterials include titanium, stainless steel, aluminum, silicone, carbonfiber, nylon, plastic/polymer, wood, rubber, gold, silver, tungsten,flex cable, neoprene, or any other suitable material. In one embodiment,components of prosthetic thumb 100 are 3D printed from Duraform EXpolymer material.

Using biocompatible materials, various embodiments of prosthetic thumb100 may be applied as an orthopedic implant that may be surgicallyimplanted into a user's thumb. This option may be applied for usershaving injuries that have crushed their finger bones without the abilityto heal or be repaired. In these situations, implantable embodiments ofprosthetic thumb 100 are able to take the place of the user's originalbones without the need for amputation.

To use, the user may simply slide distal ring 104 onto his or herresidual thumb and secure proximal anchor plate 102 above/adjacent tothe user's MCP joint 130 using hand strap 132 (FIGS. 4-5). If necessary,distal ring 104 may be further adjusted or tailored for the user via anumber of sizing shims. FIG. 8 illustrates a rear view of prostheticthumb 100, with proximal anchor plate detached from the remainingassembly. In this embodiment, distal ring 104 has been outfitted with asemi-circular shim 134, which may be inserted into an interior of distalring 104 to allow the sizing of body 110 to be adjusted incrementallyfor weight gain/loss, swelling, and/or other post-manufacture changes inthe diameter of the user's residual thumb. In further detail, a fit kit(not shown) may be provided with each prosthetic thumb 100 and mayinclude a number of shims 134. In one embodiment, each shim 134 mayapproximate a semi-circle or U-shape configured to abut an innerdiameter, d, of body 110 of distal ring 104 and may have a number ofretaining grommets 136 configured to protrude through correspondingshim-retainment apertures 138 within body 110. Each shim 132 may have adifferent thickness, t, thereby allowing the user to adjust the innerdiameter, d, of body 110 of distal ring 104 in a number of increments asrequired by the user.

Once prosthetic thumb 100 is adjusted and in place, the user may utilizehis or her natural movements of the residual thumb and/or MCP joint. Theprimary components of prosthetic thumb 100 will articulate using thesame cognitive process that was previously used for the original thumb.

FIGS. 9-11 illustrate a number of perspective views of an alternateembodiment of a bidirectional prosthetic thumb. Embodiments of thebi-directional prosthetic thumb include an adjustable ring configured toreceive and retain a user's residual thumb, along with an adjustablering tendon, both detailed below. The ring and adjustable ring tendonallow bidirectional prosthetic thumb 200 to anchor to any length ofresidual thumb, including after amputation of a thumb tip or one or morethumb segments, while providing maximum fit and use flexibility,dexterity, grip, strength, and bidirectional articulation.

To facilitate an explanation of the movement of embodiments thebidirectional prosthetic thumb, relative vertical and lateral movementsof the components of thumb are discussed below in relation to an x-axis,a y-axis, and a z-axis, as defined in FIG. 9.

Turning to the exemplary embodiments, FIGS. 9-11 illustrate numerousperspective views of one embodiment of a bidirectional andbiomechanically driven prosthetic thumb 200, as connected with a handstrap 202. In this embodiment, prosthetic thumb 200 may include anadjustable ring tendon 210 that is rotatively coupled between a proximalanchor plate 212 at its proximal end and a coupling tip 214 at itsdistal end. Proximal anchor plate 212 may rotatively couple with handstrap 202 via an eccentric articulation pivot 204 that is located abovethe user's MCP joint when prosthetic thumb 200 is installed upon theuser's residual thumb.

Articulation pivot 204 may include a strap platform 206 that is attachedor affixed to hand strap 202 to provide an appropriate alignment and/ordepth in relation to a remainder of prosthetic thumb 200. Articulationpivot 204 may also include an anchor-plate platform 216 that is disposedupon anchor plate 212 opposite strap platform 206, such that theproximal end of anchor plate 212 is disposed between strap platform 206and anchor-plate platform 216, such that an articulation joint 208 maypin anchor plate 212 between anchor-plate platform 216 and strapplatform 206 in a manner that rotationally couples the proximal end ofanchor plate 212 to strap platform 206. In this configuration, anchorplate 212 revolves relative to strap platform 206 (and hand strap 202)about articulation joint 208, or about the z-axis in a plane parallelthe x-y plane.

Adjustable ring tendon 210 may rotatively couple with the distal end ofproximal anchor plate 212 via a first hinged connection 218 and withcoupling tip 214 via a second hinged connection 220. In one embodiment,a ring 222 may be disposed upon adjustable ring tendon 210. Ring 222 maybe configured to concentrically receive and retain the user's residualthumb and may be formed of any appropriate metal and/or plasticmaterial. Ring 222 may incorporate a silicone portion or portions forimproved grip, comfort, and serviceability. These silicone portions mayreside along a lower portion of ring 222 and/or they may be incorporatedalong natural pressure points between the thumb and ring 222, such as atthe top of the proximal phalanx bone. Ring 222 may be one of a number ofinterchangeable rings, each sized to achieve an ideal fit. The rings maybe provided in a fit kit (not shown) that allows the user to select theproper ring 222 to adjust for weight gain or loss, swelling, and so on.

Ring 222 may be adjusted along the length of adjustable ring tendon 210by sliding ring 222 along a longitudinal adjustment mechanism disposedwithin tendon 210. In one embodiment shown in FIG. 11, the longitudinaladjustment mechanism may be a longitudinal adjustment channel 224 formedwithin adjustable ring tendon 210. To adjust ring 222, a user may simplyslide ring 222 along a length of channel 224 before securing ring 222via a screw 228 or any other appropriate fastener, to tendon 210 at atarget location 230. Target location 230 may be based on a length of theuser's residual thumb and result in an alignment of articulation pivot204 above/over the user's MCP joint when the user's thumb is retainedwithin ring 222. Longitudinal adjustment channel 224 may have anyappropriate length along adjustable ring tendon 210. Further, thelongitudinal adjustment mechanism may take any appropriate size, shape,type, and/or configuration. For example, in an alternate embodiment, thelongitudinal adjustment mechanism may be formed from a number ofseparate longitudinal adjustment holes disposed along the length ofadjustable ring tendon 210.

As shown in FIGS. 9-11 and discussed above, coupling tip 214 mayrotatively couple with the distal end of adjustable ring tendon 210 viasecond hinged connection 220. In one embodiment, second hingedconnection 220 may be a screw configured to be tightened at any desiredangle such that second hinged connection 220 may be adjusted through 360degrees of rotation, limited only by interference with the othercomponents of prosthetic finger 200. In this regard, second hingedconnection 220 offers infinite adjustment options within a full range offeasible and/or desirable fingertip angles.

Coupling tip 214 may include a tip pad 232. Tip pad 232 may be formedfrom a soft-textured silicone or other material that mimics the textureof a real finger. This aids with gripping and provides a softer touch. Acap may also be fitted over tip pad to further provide a realistic thumbappearance. In one embodiment, a touchscreen mechanism (not shown) maybe provided to allow the user of prosthetic thumb 200 to operatecapacitive touchscreens, which react to the body's natural current. Thetouchscreen mechanism allows the user to direct his or her body currentthrough coupling tip 214.

As discussed above, prosthetic thumb 200 is designed for bidirectionalarticulation. Specifically, proximal anchor plate 212, adjustable ringtendon 210, and distal coupler 214 may together form an articulationassembly 215 that moves within two perpendicular planes. First,articulation assembly 215 rotates laterally relative to articulationpivot 204 via articulation joint 208, providing prosthetic thumb 200with a first direction of movement about an axis parallel to the z-axisand within a plane parallel the x-y plane. Second, first and secondhinged connections 218 and 220, which rotatively couple adjustable ringtendon 210 between proximal anchor plate 212 and distal coupler 214,respectively, provide articulation assembly 215 with a second, verticaldirection of movement about an axis parallel to the y-axis and within aplane parallel to the x-z plane. As a result, the user may achieve morelifelike movement of distal coupler 214 that emulates the naturalarticulation of a thumb by moving his or her residual thumb laterally(e.g., adducting and/or abducting the residual thumb) within ring 222 toactuate articulation assembly 215 of prosthetic thumb 200 in the firstdirection, and by moving his or her residual thumb vertically withinring 222 to actuate articulation assembly 215 of thumb 200 in the seconddirection, thereby achieving both lateral and vertical articulation ofcoupling tip 214.

Embodiments of prosthetic thumb 100, 200 are custom designed andindividually fitted to accommodate a variety of differing userconditions. In this regard, each thumb 100, 200 may be custommanufactured to fit a particular patient or user, providing both customfunctionality as well as a mechanical match to the anatomical jointarticulation of the user.

To further provide better aesthetics, embodiments of prosthetic thumb100, 200 may be coated with films and/or colorings matched to the user'sskin tone. An additive manufacturing process (i.e., 3D printing)facilitates this ability to customize the intricacies of the prostheticdesign in order to optimize prosthetic finger 100, 200 for each patient.

Various embodiments of thumb 100, 200 may be formed of any suitablestructural material that is non-irritating to human skin and allows theuser to operate the prosthetic with confidence. Exemplary materialsinclude titanium, stainless steel, aluminum, silicone, carbon fiber,nylon, plastic, wood, rubber, gold, silver, tungsten, flex cable,neoprene, or any other suitable structural material. In one embodiment,the device may be 3D printed from Duraform EX polymer material.

Portions of embodiments of prosthetic thumb 100, 200 may be used fordiffering conditions of the user. Embodiments can accommodate varyinglevels of thumb loss, i.e., for thumb tips or full thumbs. Additionally,using biocompatible materials, various embodiments prosthetic thumb 100,200 may be applied as an orthopedic implant that may be surgicallyimplanted into a user's thumb. This option may be applied for usershaving injuries that have crushed their thumb bones without the abilityto heal or be repaired. In these situations, implantable embodiments ofprosthetic thumb 100, 200 are able to take the place of the user'soriginal bones without the need for amputation.

Once thumb 100, 200 (adjusted or otherwise) is in place, the user mayutilize his or her natural finger movements. The rotatively coupledcomponents of thumb 100, 200 will articulate using the same cognitiveprocess that was previously utilized for the original thumb.

Embodiments of thumb assembly 100, 200 described above exhibit numerousunique characteristics and provide a variety of medical benefits. Anindividual's unique physiology and lifestyle patterns dictate thefunction and performance expected of his or her hands. Using embodimentsof the prosthetic thumb assembly described herein, patients may regainindependent control of their hands, whether at work or at play. Eachdevice is custom designed and manufactured for a specific individual,and incorporates features that allow for further fine-tuning andadjustment of fit to account for post-manufacturing fluctuations (e.g.,shims, interchangeable rings), enabling the device to fit the user in amanner that allows for a biomechanically driven, low profile,lightweight, highly functioning return to the user's everydayactivities, no matter what those activities might entail. A few examplesinclude typing, playing the piano or another instrument, woodworking,and much more.

Embodiments of the biomechanical finger assembly described above arebody powered, accommodate bidirectional movement, and feature linkedcomponents that articulate when the user simply moves his or herresidual thumb. Beyond allowing for a simple, elegant, and streamlineddesign that offers strength in the lowest possible profile design,employing the user's own biomechanics to drive embodiments of thumb 100,200 provides a host of medical benefits to the user, including reducedswelling of and increased circulation to the residual thumb and the handas a whole, and supporting healthy joints in the injured thumb andadjacent fingers.

Although the above embodiments have been described in language that isspecific to certain structures, elements, compositions, andmethodological steps, it is to be understood that the technology definedin the appended claims is not necessarily limited to the specificstructures, elements, compositions and/or steps described. Rather, thespecific aspects and steps are described as forms of implementing theclaimed technology. Since many embodiments of the technology can bepracticed without departing from the spirit and scope of the invention,the invention resides in the claims hereinafter appended.

What is claimed is:
 1. A prosthetic thumb assembly, comprising: acoupling tip; a distal ring configured to concentrically receive aresidual thumb of a user, the distal ring having a first operable hingedconnection with the coupling tip; a proximal anchor plate having asecond operable hinged connection with the distal ring, and an anchorattachment point located upon the anchor plate and configured forrotatively connecting the proximal anchor plate to the user; and arocker formed in an H-shape having a first end and a second end inopposition to one another, the first end forming a first split prong ofthe H-shape, the first end having a third operable hinged connectionwith the coupling tip, the second end forming a second split prong ofthe H-shape, the second end having a fourth operable hinged connectionwith the proximal anchor plate, wherein: the first and second operablehinged connections define a midline relative to a z-axis; the thirdoperable hinged connection is located below the midline; the fourthoperable hinged connection is located above the midline; and thecoupling tip is articulated in response to a pulling force provided bythe rocker.
 2. The prosthetic thumb assembly of claim 1, furthercomprising a hand strap configured for attachment about a hand of theuser, the hand strap anchored to the anchor attachment point of theproximal anchor plate.
 3. The prosthetic thumb assembly of claim 1,wherein: the first and the third operable hinged connections combine toform a distal coordinated pivot point anchored on the coupling tip; thesecond and the fourth operable hinged connections combine to form aproximal coordinated pivot point anchored on the proximal anchor plate;and the distal ring and the rocker are independently suspended betweenthe distal coordinated pivot point and the proximal coordinated pivotpoint.
 4. The prosthetic thumb assembly of claim 3, wherein the distalring and the rocker are indirectly coupled via the distal coordinatedpivot point and the proximal coordinated pivot point.
 5. The prostheticthumb assembly of claim 1, wherein the coupling tip includes a tip pad.6. The prosthetic thumb assembly of claim 1, wherein: the first operablehinged connection of the distal ring with the coupling tip includes afirst pair of distal pivotal hinges that are symmetric about acenterline relative to a y-axis; and the second operable hingedconnection of the distal ring with the proximal anchor plate includes afirst pair of proximal pivotal hinges that are symmetric about thecenterline.
 7. The prosthetic thumb assembly of claim 6, wherein: thethird operable hinged connection of the rocker with the coupling tipincludes a second pair of distal pivotal hinges that are symmetric aboutthe centerline; and the fourth operable hinged connection of the rockerwith the proximal anchor plate includes a second pair of proximalpivotal hinges that are symmetric about the centerline.
 8. Theprosthetic thumb assembly of claim 1, further comprising a plurality ofsizing shims, each having a different thickness and configured toconform to an inner surface of the distal ring.
 9. A biomechanicallydriven prosthetic thumb, comprising: a coupling tip; a proximal anchorplate configured for attachment to a hand strap, the hand strapconfigured for attachment about a hand of a user; a distal ring having abody with an outer surface and an inner surface, the inner surfaceconfigured to concentrically receive a residual thumb of the user; andan H-shaped rocker offset from the outer surface of the body of thedistal ring, wherein the distal ring and the H-shaped rocker areindependently and pivotally suspended between the coupling tip and theproximal anchor plate via a distal coordinated pivot point anchored uponthe coupling tip and a proximal coordinated pivot point anchored uponthe proximal anchor plate.
 10. The biomechanically driven prostheticthumb of claim 9, wherein: the distal coordinated pivot point comprisesa first operable hinged connection between the distal ring and thecoupling tip and a third operable hinged connection between the H-shapedrocker and the coupling tip; and the proximal coordinated pivot pointcomprises a second operable hinged connection between the distal ringand the proximal anchor plate and a fourth operable hinged connectionbetween the H-shaped rocker and the proximal anchor plate.
 11. Thebiomechanically driven prosthetic thumb of claim 10, wherein: the firstand second operable hinged connections define a midline relative to az-axis; the third operable hinged connection is located below themidline; and the fourth operable hinged connection is located above themidline.
 12. The biomechanically driven prosthetic thumb of claim 10,wherein: the first operable hinged connection of the distal ring withthe coupling tip includes a first pair of distal pivotal hinges that aresymmetric about a centerline relative to a y-axis; the second operablehinged connection of the distal ring with the proximal anchor plateincludes a first pair of proximal pivotal hinges that are symmetricabout the centerline; the third operable hinged connection of the rockerwith the coupling tip includes a second pair of distal pivotal hingesthat are symmetric about the centerline relative to the y-axis; and thefourth operable hinged connection of the rocker and the proximal anchorplate includes second pair of proximal pivotal hinges that are symmetricabout the centerline.
 13. The biomechanically driven prosthetic thumb ofclaim 10, wherein the H-shaped rocker is configured to utilize movementsof the residual thumb within the distal ring to provide a pulling forceto articulate the coupling tip.